Exam 2

Respiratory System Lymphatic System

Basic functions of the respiratory system:

• gas exchange (O2, CO2)

• pH regulation

• olfaction (sense of smell)

• filter inspired air

• phonation (sound production)

Why do cells need oxygen?

• for cellular respiration → to make ATP

What is Cellular respiration?

• process in which nutrients are converted to useful energy for the cell

• generates ATP

• C6H12O6 + 6 O2 → 6 CO2 + 6 H2O

The respiratory system anatomy is classified by _____ or _____

• Structure or function

2 zones in respiratory system anatomy [functionally]

1. Conducting zone

2. Respiratory zone

what is the conducting zone?

• site that moves air in/out of lungs

  • nose, pharynx, larynx, trachea, bronchi, bronchioles and terminal bronchioles [only moving air]

what is the respiratory zone?

• site of gas exchange

  • respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli

How is the respiratory system anatomy separated structurally?

• upper / lower respiratory system

what are the organs in the upper respiratory tract?

• nasal cavity

• pharynx

what are the organs in the lower respiratory tract?

• larynx

• trachea

• primary bronchi

• lungs

all of the respiratory tract is lined with?

• Cilia / Ciliated mucous membranes

• constantly swallowing bits of mucus that are coming from below and up above

• all move in unison

Cilia in upper respiratory tract move mucous and trapped particles where?

• down toward pharynx

Cilia in lower respiratory tract move mucous and trapped particles where?

• up toward pharynx

Why does cilia in upper/lower respiratory tract move mucous and trapped particles down/up toward pharynx?

• because it continually almost wash with mucus with these surfaces

  • if sick — you’re gonna end up coughing out or spitting out

• always moving the stuff trapped in your mucus towards the pharynx

Other name for pharynx

Throat

structure of Larynx (voice box)

• contains vocal chords

• 2 inch tube

Larynx (voice box) function

• deglutition

  • airway closes when you swallow

• respiration/ventilation

• phonation

Trachea function

• move air in and out of the lungs

• lined with cilia

  • push stuff up because the pharynx is now superior to trachea

Trachea structure

• tube that doesn’t change in size because it needs to be the same size

• pretty big so we don’t reduce the airflow into the lungs/of the lungs

Lungs receive blood from…?

• pulmonary arteries

• bronchial arteries

what are pulmonary arteries?

• low O2 blood / deoxygenated blood from right ventricle

what are bronchial arteries?

• high O2 blood / oxygenated blood from left ventricle

what are pleural membranes

serous membranes → that line body cavities that are not exposed to the outside

each lung enclosed by double-layered pleural membrane. what are these pleura? [2]

• parietal pleura

• visceral pleura

what is parietal pleura

outer layer

what is visceral pleura

inner layer

• close to organs

what is pleural cavity

the space between layers

what does pleural fluid do?

• reduces friction

• produces surface tension (stick together)

what is the branching of bronchial tree

trachea → primary bronchi → secondary bronchi → tertiary bronchi → bronchioles → terminal bronchioles (last airway where you just have a conducting zone; not exchanging air yet)

how many orders of branching

~ 25

what is Carina

above split of primary bronchi

• cough reflex

  • most robust / forceful

which branch are non-ciliated

smaller bronchioles

what rings disappear

cartilage rings

as cartilage decreases…

smooth muscle increases

what happens in the airway in the Sympathetic ANS

epinephrine coming from the adrenal glands → smooth muscle relaxes → dilation of airway

what happens in the airway in the Parasympathetic ANS

smooth muscle contraction → constriction of airway

what happens in the airway when used Histamine (mediator of allergic reactions)

close/constrict of airways

what are Lobules of Lungs

wrapped in elastic connective tissue and contains:

• lymphatic vessel

• arteriole

• venule & branch from terminal bronchiole

what is compliance

• ability to stretch/recoil

• helps getting the air back out

what is alveolus

• cup-shaped outpouching

  • ~ 300 million in lung = surface area of racquetball court

2 types of alveolar epithelial cells

1. Type 1 alveolar cells (pneumocyte type 1)

2. Type 2 alveolar cells (pneumocyte type 2)

what is Type 1 alveolar cells (pneumocyte type 1)

• site of gas exchange

• simple squamous cells

• form nearly continuous lining

• ~95% of cells

what is Type 2 alveolar cells (pneumocyte type 2)

• secrete alveolar fluid

  • (surfactant reduces tendency to collapse)

what is Surfactant

mix of phospholipids and lipoproteins that reduce surface tension

• if surface tension too high = alveoli collapses

what do alveolar macrophages do

remove fine dust, etc.

• phagocytes

3 steps for air and gas exchange

1. Pulmonary ventilation/breathing

2. External (pulmonary) respiration

3. Internal (tissue) respiration

what is pulmonary ventilation/breathing

• inhalation & exhalation

• exchange of air between atmosphere and alveoli

what is external (pulmonary) respiration

exchange of gases between the alveoli and blood

what is internal (tissue) respiration

exchange of gases between systemic capillaries and tissues

what is boyle’s law

pressure of a gas in a closed container is inversely proportional to the volume of the container

inhalation/inspiration

• achieved by increasing size of lungs

• lungs must expand → increasing lung volume = decreases pressure below atmospheric pressure

• is active = contraction of muscles required

• can increase # of muscles if forced inhalation

  • diaphragm & external intercostal muscles

(all about pressure differences)

exhalation/expiration

• lung pressure is GREATER > than atmoshpheric pressure then air rushes out

  • intrapulmonary volume ⬇ + diaphragm (⬆) and external intercostals relax

• normally passive — muscles relax

  • based on elastic recoil of chest wall and lungs due to:

    • elastic fibers

    • surface tension of Alveolar fluid (important for lung recoiling)

Air pressure differences drive _____ in lungs

airflow

3 factors that affect rate of airflow and ease of pulmonary ventilation

1. Alveolar fluid surface tension

   • causes alveoli to assume smallest possible diameter

   • accounts for 2/3 of lung elastic recoil

2. Lung compliance

   • high compliance means lungs and chest wall expand easily

   • related to elasticity and surface tension

3. Airway resistance

   • larger diameter airway has low resistance

   • regulated by diameter of bronchioles via ANS (Autonomic nervous system)

Alveolar surface tension

• surface tension

  • attracts liquid molecules to one another at a gas-liquid interface

• surfactant

  • made by Type 2 Alveolar

  • detergent-like complex

  • reduces surface tension of alveolar fluid discouraging alveolar collapse

what is a Surfactant

• prevents the alveoli to collapse

  • made by Type 2 alveolar

• detergent-like complex

• reduces surface tension of alveolar fluid

we need _______ _______ but not too much

surface tension

Lung Compliance

a measure of the change in lung volume that occurs with a given change in transpulmonary pressure

• normally HIGH compliance due to…

  • distensibility of the lung tissue (a lot of elastic tissue)

  • alveolar surface tension

what is lung compliance diminished by?

• nonelastic scar tissue (fibrosis)

• reduced production of surfactant

• decreased flexibility of the thoracic cage [happen with age]

• pulmonary edema

all decrease lung compliance

Airway Resistance

resistance is usually insignificant due to…

• large airway diameters in the first part of the conducting zone

• progressive branching of airways as they get smaller, increasing the total cross-sectional area

what happens in increased airway resistance?

• breathing become more difficult/strenous

• severely constricting or obstruction of bronchioles

  • can prevent life-sustaining ventilation

  • acute asthma attacks can stop/inhibit ventilation

• Epinephrine will lead to smooth muscle relaxation & dilation of the airways (lined w/ smooth muscle)

  • ex: Epiphen inhalers

what is Ventilation

amount of air reaching the alveoli

what is Perfusion

blood flow reaching the alveoli

Ventilation and perfusion must be ______ for efficient gas exchange

matched (coupled)

what affects perfusion/blood flow?

vasoconstriction/vasodilation

• affect diameter of airways

main idea of Ventilation-Perfusion coupling

to make sure airflow & blood flow are matched/equal

Ventilation-Perfusion coupling in the arterioles

changes in partial pressure OXYGEN (P O2) in the alveoli cause changes in the diameters of the arterioles

• HIGH alveolar O2 → arterioles DILATE

• LOW alveolar O2 → arterioles CONSTRICT

Ventilation-Perfusion coupling in the bronchioles

changes in partial pressure CARBON DIOXIDE (P CO2) in the alveoli cause changes in the diameters of the bronchioles

• HIGH alveolar CO2 → bronchioles DILATE

• LOW alveolar CO2 → bronchioles CONSTRICT

gas exhange involves _______ _______ gradients

partial pressure

what is Air

mixture of gases

• nitrogen, oxygen, water vapor, and carbon dioxide

what is partial pressure

the pressure for a specific gas

• determined by multiplying the atmospheric pressure by the percentage of the specific gas in the atmospheric air

• atmospheric pressure = 760 mmHg

partial pressure of a gas in solution depends on 2 elements

1. concentration

2. solubility

relationship of concentration + partial pressure

the greater > the concentration of a gas = the greater > its partial pressure

what is solubility

how easily does it dissolve in the solution

solubility of Oxygen (O2)

low solubility; doesn’t like to hang out with water, hence the hemoglobin!

solubility of Carbon Dioxide (CO2)

better solubility; easy to get into water

how does gas partial pressure in liquids work

explains how solubility of gas is related to diffusion

• it bends

  • HIGHER pressure = N2 comes in you MORE

gas stays in solution when?

1. higher partial pressure

2. has high solubility in water

   • AKA: Carbon dioxide

the alveoli are lined with very small _____ ______

blood vessels

what does the alveoli do?

GAS EXCHANGE:

• blood gets rid of Carbon Dioxide and picks up Oxygen from the air we breathe in

what is external respiration in lungs?

pulmonary gas exchange → Oxygen in; Carbon Dioxide out

• O2 and CO2 diffuse independently

external respiration of Oxygen

diffuses from alveolar air into → blood of pulmonary capillaries

• diffusion continues until Partial pressure O2 of pulmonary capillary blood matches = Partial pressure O2 of alveolar air

external respiration of Carbon Dioxide

diffuses from deoxygenated blood in pulmonary capillaries into → alveolar air

• continues until partial pressure CO2 blood reaches 40 mmHg

what is internal respiration ?

gas exchange between blood and body tissues

• at rest, only about 25% of the available oxygen is used

• oxygen:

  • moves from systemic capillaries → tissues

• carbon dioxide

  • moves from tissues → systemic capillaries

• rate of these gases diffuse is dependent on their partial pressures

  • gases move from an area of HIGH partial pressure to LOW partial pressure

internal respiration of Oxygen

oxygen diffuses from systemic capillary blood into → tissue cells

internal respiration of carbon dioxide

diffuses from tissue cells into → systemic capillaries

• partial pressure CO2 blood reaches 45 mmHg

what is oxygen transport?

• 1.5% dissolved in plasma

• 98.5% bound to hemoglobin (Hb) in RBCs

  • Heme has 4 iron molecules

    • each can bind one oxygen or carbon monoxide

    • O2 + Hb = Hb-O2 (Oxyhemoglobin)

why does oxygen transport requires hemoglobin?

oxygen has low solubility in water + plasma membrane is an aqueous solution… so we need hemoglobin to bind with oxygen to be able to transport properly

what is Affinity

the ability of Hemoglobin (Hb) to hold Oxygen

What happens when the curve shifts to RIGHT → ?

• Affinity of hemoglobin to Oxygen ⬇

• ⬆ Oxygen release

= low pH (acidic), high temp, high partial pressure CO2

what happens when the curve shifts to LEFT ← ?

• affinity of oxygen to hemoglobin ⬆

• ⬇ oxygen release

= high pH (basic), low temp, low partial pressure CO2

the affinity for oxygen to hemoglobin and how much saturation there is, is directly related to?

the pressure of oxygen

the more oxygen, the higher _______

saturation

3 other factors that affect affinity of Hemoglobin for O2

1. Acidity

2. Pco2

3. Temperature

characteristics of metabolically active tissues

• need O2

  • to do more cellular respiration to make more ATP to fuel more reactions

• produce acids

• has CO2

• heat as wastes

Factors that affect affinity of Hb for O2: the Bohr Effect (Acidity factor)

⬆ acidity (decreased pH) = ⬇ affinity of hemoglobin for Oxygen

• increasing acidity enhances unloading/release of O2

• shifts curve to right →

• ex: metabolically active tissue

-OR-

⬇ acidity (increase pH) = ⬆ affinity of hemoglobin for Oxygen

• decreasing acidity = decrease release of O2

• shifts curve to left ←

what if a tissue is acidotic?

it is more active, therefore need more oxygen

• so, decrease how hard hemoglobin is holding oxygen (decrease affinity) = increases how much oxygen gets to that tissue (increases oxygen release)

Factors that affect affinity of Hb for O2: Partial pressure of CO2

⬆ Pco2 = ⬆ Oxygen release = ⬇ affinity

• shifts curve to right →

• Unloads O2 more easily

• Low blood

• CO2 + H2O → H+ + HCO3- (bicarbonate)

Factors that affect affinity of Hb for O2: Temperature changes

⬆ temperature = ⬆ oxygen release = ⬇ affinity of hemoglobin for O2

• During hypothermia, more oxygen remains inbound

• Heat is byproduct of high metabolic activity

what is the difference between fetal and maternal hemoglobin?

fetal hemoglobin has a HIGHER > affinity for oxygen than adult hemoglobin

• Hb-F can carry up to 30% more oxygen

• maternal blood’s oxygen readily transferred to fetal blood